open any of the wav's in notepad... and check out the last few characters.

LISTB INFOICRD 2000-04-06 IENG Deepz0ne ISFT Sound Forge 4.5

Apparently sound forge tags the wavs, Deepz0ne would be the author of the wav... Deepz0ne is also the author of a crack for SoundForge 4.5... Oups, looks like even Microsoft uses pirated material. I saw this on slashdot awhile back.